text: (function(){
  
    'use strict';
  
    var image = document.getElementById('js-image');
  
    var button0   = document.getElementById('js-button-0'),
        button20  = document.getElementById('js-button-20'),
        button50  = document.getElementById('js-button-50'),
        button70  = document.getElementById('js-button-70'),
        button100 = document.getElementById('js-button-100'),
        buttonAnimation = document.getElementById('js-button-animation');
  
    button0.addEventListener('click', function() {
      image.style.webkitMaskBoxImage =
        '-webkit-linear-gradient(right, white, white 0%, transparent 10%, transparent 0%)';
    }, false);
  
    button20.addEventListener('click', function() {
      image.style.webkitMaskBoxImage =
        '-webkit-linear-gradient(right, white, white 20%, transparent 30%, transparent 20%)';
    }, false);
  
    button50.addEventListener('click', function() {
      image.style.webkitMaskBoxImage =
        '-webkit-linear-gradient(right, white, white 50%, transparent 60%, transparent 50%)';
    }, false);
  
    button70.addEventListener('click', function() {
      image.style.webkitMaskBoxImage =
        '-webkit-linear-gradient(right, white, white 70%, transparent 80%, transparent 70%)';
    }, false);
  
    button100.addEventListener('click', function() {
      image.style.webkitMaskBoxImage =
        '-webkit-linear-gradient(right, white, white 100%, transparent 110%, transparent 100%)';
    }, false);
  
    buttonAnimation.addEventListener('click', function() {
      Velocity(image, 'stop');
      Velocity(image, {
        tween: 100
      }, {
        duration: 1000,
        easing: 'ease',
        progress: function(elements, c, r, s, t) {
          var i, len;
  
          for (i = 0, len = elements.length; i < len; ++i) {
            elements[i].style.webkitMaskBoxImage =
              '-webkit-linear-gradient(right, white, white ' + t + '%, transparent ' + (t + 10) + '%, transparent ' + t + '%)';
          }
        }
      });
    }, false);
  
  }());
  